Question My computer is having some weird visual crashing issues, any help?

Mar 17, 2019
So I refurbished an old pc i found in my garage, had been sitting there for about 7 years. It has been working fine up until about two days ago. I noticed that the fans and everything else was on, but nothing was displaying on the monitor. I did some tests and its not a monitor issue. I left the power cord unplugged overnight, and it "works" the next day. It will be working fine for 10-15 minuets, then the whole screen will go to a random color, and wont respond to anything. If i leave the power cord unplugged for 30+ minutes, then it turns back on but does the same thing. if i restart it, it wont show anything on the monitor. it seems to last longer the longer i leave it unplugged. Does not give me a beep code.

I think it may be a graphics card issue, but i dont have much experience with this as i usually use a mac.

Computer specs are,

Processor- Intel Pentium Dual core Processor

Ram- 7gb ( 3 originally, added new in)

Card reader- 16 in one

windows ten

sorry if this is not enough information, but i cant really access the information right now with the state of my comp.