Computer crashes every now and then

My computer is having problems!! Every once in a while it will glitch really bad. Sometimes when im on Chrome it just crashes. Then it glitches and the bottom blue bar is at the top. but you cant click on anything. sometimes you can see the "Send Error Report" or whatever it says. i can click on it sometimes but even if i do it wont go back to normal. i eventually have to restart the computer and it is just fine until i leave it alone for a day or two or even as low as an hour. Please help.i dont think it is a virus (but it could be). i have Microsoft Security Essentials and when i do the full scan it doesnt pick up anything. Any suggestions? (sorry for grammer or spelling. it is one thirty in the morning and i am extreamly tired...

in my suggestion go for a thorough cleaning of your computer... including checking of bad sectors of your hard drive, defragmentation etc... I use AVG PC tuneup for the same. Delete the unnecessary programmes in startup, and increase your virtual memory! You can't rely upon Microsoft Security Essentials go for some reputed Antivirus like AVG...

your computer might be infected by a virus.
try reinstalling your os