This started happening after you got a virus right? Try reinstalling java. Make sure it's the 64 bit version if you have a 64 bit os.
This is going to sound stupid, but have you tried running it as administrator? My client wasn't working until I did that; I'm still not sure what was wrong with it.
download malwarebytes http://www.malwarebytes.org/downloads/ and run a full scan with it. if that doesnt work, delete sys32
I know what your problem is, minecraft needs a decent amount of RAM to run here is your simple and easy solution www.downloadfreeram.com