First, be aware that this Celeroin eMachine of yours is known to have a lot of early failures... perhaps the highest in the industry. The slowdown could be the early stages of that failure. Repairs involve replacing the motherboard, and power supply, at a cost exceeding $200. Or it could be the eMachines hard drive, which is usually a TriGem (Ugh) or a Maxtor. It may need a replacement, as it slows down before it quits.
As for what the scans show, you have to have a lot of memory... the full 2 GB, methings, to handle all the stuff you have installed. So unless the memory is full, add enough to max it out... unless you take my warning about the EMachine failures.
You have way too much junque installed with the good stuff, and too many processes going on. You are reporting 53% of your memory in use for simple tasks. Think about what you have:
SuperAntiSpyware
System Mechanic
System Mechanic Popup Blocker
Panicware Popup Stopper
Kaspersky Popup blocker
Kaspersky Security.
Registry Shave
Stumble Upon IE Bar
BitDefender remnants
WinssWebAgent
Ewido Online Antispyware, a very old, and no longer working or supported spyware program
SpyBot S&D a fun, but worthless program
Adaware 2007
Trend Micro Stats (probably HiJackThis)
Google Updater
Messenger Client
then your communications and access software.
You are overloading your computer with often worthless stuff.
Consider using
Adaware + one other spyware program.
Windws Defender
Use Firefox 3.0 to run your popup blocker automatically.
SuperAntiSpyware is good, but not the best, antispyware
If you use System Mechanic, are you happy with it? If so, drop a lot of the other stuff.
With a lot of installs, you could run Windows XP in repair mode to touch things up a bit, but the eMachine version will not do that.
You probably would benefit from a registry cleanup from what I see of remnants, so you might consider downloading and running CCleaner.
Good luck to you. Let us know what you decide to do.
If you keep the eMachines, replace the power supply with a rugged one of 400 watts at about $65. It may help, but the failure is usually the motherboard.