Hi Janet,
Firstly, there's likely nothing wrong with your VAIO-- it just needs to be reinstalled. I'm a small business owner in IT. I specialize in mainly residential clients, as the rest of the local IT people all chase businesses. Anyway, a reinstall of your VAIO, using a stock Windows 7 image (not the Sony factory recovery) is the way to get the best performance from your laptop. Most machines do well to have a reinstall by the three year mark. If you're doing it right, you should have two back-ups of your data- NOT on the computer. That way, the reinstall isn't such a big deal. Later, I'll tell you how to make it even easier, next time.
Stop now & back-up all of your data if you haven't, as yet. Email is dependent on how you have yours set up. If you always access it online, then it will be there. If you use a program on your computer & do not have it save a copy to the server, you may need to locate & backup that folder from your computer.
Yes, you're quite correct in suspecting the VIAO software as a source of sluggishness. Sony was even
shot down at one point for attempting to charge a fee to sell you it's PC's without all of the junkware. Suffice to say, you generally don't need anything but the drivers which run the actual hardware. One exception would be proprietary software to control your specific keyboard's Fn (function) keys. Put another way- when you're done installing what you need, device manager will let you know if anything is missing- & then you can go and fetch only that from Sony.
Luckily, most computers have a folder which holds all of the maker's drivers in one spot- which you can copy off to an external device. VAIO's usually use C:\Drivers, but have a poke around if that's not the right location. Look for something called C:\Sony\Drivers, or C:\Programs\VAIO etc...You can use
Belarc Advisor to get a report of what's actually on your current system & save that, too. Makes it easy to reinstall drivers when you know what you've got!
Keep in mind that when you install with a plain Win 7 disc, you also need your product key handy- meaning the one that's on the label on the computer. When re-activating afterwards you'll likely need to use the automated telephone activation- takes about five minutes of button pushing, & you're done...(you'll see "activate now" by right-clicking My Computer>properties/system information>lower-right of screen, ).
Windows images are stored
here. They are large files so, even using a torrent program, it may take a while. Choose your version & then choose either 32 or 64bit (matching your *current system). This will be found within Belarc's report. Once the image is downloaded (& you can check the MD5 sum, if you wish, per the article linked), you'll need to burn the image to a DVD (or create a bootable USB, but the DVD is easier). You can use your own software (look for the choice of "burn image") or download & install
Imgburn (free) via ninite as they make sure no malware gets attached (tick Imgburn, get installer, run). *Btw- your Windows 7 key will activate both 32 & 64 bit- so really the choice depends on whether your hardware ever had 64 bit drivers & whether you will ever have more than 2GB of RAM. If no- then stick with 32 bit.
Once you have the DVD burned, you pop it into your VIAO & shutdown. Start up again & at the very first hint of something on-screen, look at the bottom left-hand side of your screen for key info on getting to "setup" or "boot order", usually F2. On some VAIO's, you start up with the "assist" key to reach this.
This, BIOS, is where you want to alter the machine to force it to look at your DVD, 1st, rather than booting back to the hard drive. This is sometimes tricky- as some machines give you almost no time to read before booting- so be patient that it may take a few goes. When you do finally get to the installation screen for Win 7, choose "custom" & then choose the largest partition to install your new Windows to. You'll be warned that there's already an OS there & that all data will be lost-- click continue.
Once windows is installed, you load your drivers you saved to the external drive at the beginning. Start with the network (LAN/wifi) & then activate Windows before going any further. If there's any issue, you can always fall back to the factory recovery.
A few tweaks: right-click the desktop>personalize>change desktop icons>tick user/computer/recycle bin. For speed: right-click computer>properties>advanced system settings>advanced tab>performance>set for best performance & tick: show thumbnails, enable peek, smooth fonts, use visual styles, apply. Right-click recycle bin>properties>set "custom size" to 500mb from the outrageous & massive amount MS wants to steal from you for your rubbish. If your battery is shot (likely is, by now) & you mainly run off power, then go to power settings, in control panel, and set yours to "high performance". Go back to ninite.com & grab 7-zip, LibreOffice, Auslogics defrag, Avast AV (if you don't have one), Sumatra PDF, and anything else you find of interest. The one installer will install everything for you- all junk removed.

Run Auslogic. Go to settings>program settings>"Algorithms" tab>tick delete temp files, skip files larger than 10mb, & move system files to the beginning of the disk. Then, run the defrag.
Now- once you get things set as you like them, you can create your own image of the way things are at that moment. Go to start>all programs>maintenance>backup & restore>create a system image. Send it out to your external drive. If you ever have a bad virus or any other issue, you can go back to this image within minutes- fully activated & ready to go. Be sure to also make the recovery CD while you're there.
That's about it. I recommend a reinstall over a "clean up" because after a certain point, it's impossible to gain back the performance due to registry bloat, corrupt files, fragmentation (both of the registry & hard disk, malware & virus damage, etc)...Cleaners simply cannot undo it. Reinstall is the best value for your time spent, bar none.
Cheers & good luck!