Hey George,
I have got to say using a Gateway may not be your best choice, but I digress.
Are you getting a BSOD?
You can try opening and removing the RAM and re-installing it, making sure to have a good fit. Or replace the RAM if that is an option.
I know this isn’t RAM related but you could run a CHKDSK from the run dialog box and check your hard drive.
There could be a potential for a failing power supply as well, or a virus.
Without more information it is really hard to say., but those are a few things to try.
Hope this helps.