I suspect you have a number of problems, making it difficult to fix any of them.
But I have forgotten what is the brand, and model of computer or motherboardk and the full configuration...
I suspect you have something that is affected by vibration or heat...
Some things to try:
Buy a small unit of Thermal paste. Remove your CPU, use denatured alcohol to carefully clean off the old paste from the CPU and socket. Then apply a very thin coating of new paste.
Check very carefully to assure that your CPU Cooler hold down clamps are not broken or loose. Some that clamp onto a plastic fram for the CPU do break easily but you cannot easily see the break. They just don't hold the CPU cooler tight enough.
CPU coolers are usually very inexpensive. I would replace the cooler as a unit... which with careful shopping can be done for $12.
I would replace the power supply with another... even a used one, for a couple of days... It may be worth it to replace your existing power supply with a good one made by FSP group... or Sparkle... or other in the 400 watt plus range...
You cannot accurately test a power supply, but they can give you a lot of intermittent troubles... Anything over 400 watts should be fine for doing the analysis for a couple of days.
I would remove Norton 360... It is old, and never was much good when it was new. Then install Microsoft Security Essentials (free), Avast (free) or Avira Antivir (free), MalwareBytes (free version), and SuperAntiSpyware (free version) You can find them all at
www.filehippo.com and many other sites.
Toss Norton and continue to use the above four and update them daily... they will help you determine whether you are getting an infestation.
Next is memory. If you do not have at least 1 GB or memory, upgrade it to that level... If you can afford an upgrade to 2 GB, that is preferable.
Next, tell us about your hard drive... how old, what brand,
Tell us, also, about the video graphics card brand and model, as well as age.
You should NEVER have to reseat your video card more than once. Why were you doing that. Handling that card, and performing reseating operations can damage the socket, the motherboard, and the video graphics card.
Then I would reformat your hard drive and do a complete clean install... slowly, while keep notes of what you are doing.
The problem has to be in the CPU (usually not) CPU cooler (much more often), Video Card (there are huge numbers of bad ones out there... that give intermittent problems one day and are fine the next, Hard Drive. Software installed to the hard drive, or Power Supply. Rarely, very rarely, it is the motherboard. And ti can be memory or a damaged memory socket... or one of the adapters to which you connect.
But we may have other comments after we know the components by brand, age, and specs.
We will find the problem....