Why won't my computer restore to an earlier date?

Computer gone so slow but when restore to an earlier date it goes back to normal?

• I have restored it 4 times, every time i restore to an earlier date it works perfectly/normal, then a few days later the computer goes dead slow, when booting up or shutting down it makes a crackling sound and it takes ages to boot up and shut down same applies to opening files. I have ran norton 360 -no problem. laptop is ACER- WINDOWS XP I have upgraded the RAM by 3GB a while ago and was working perfectly so surely can't be that. I often get a blue screen with loads of writing saying something like windows has to shut down to prevent damage?!? Then it wont boot up automatic so i hold down the on/off button, when loading up the scan for files abd folder kicks in taking ages again.

• Answer:

  Blue screens generally are a sign of overheating, not enough power or bad RAM or a bad RAM slot in the computer. Crackling sounds aren't a good sign and usually are the sounds of sparks.. I would check your power cable for any splits or power supply. It may be a software issue, if so instead of restoring it to an earlier point in time try a factory reset and try from scratch. If it keeps doing it then, it is obvious it is a hardware issue.