Tons of lag on minecraft servers PLEASE HEP

for about a week, i would get on a server and it would be fine for like 2 mins then it would get stuck on a frame for a few secs, play a few frames, then get stuck again and so on. its unbearable to play online and i need help. and my ONLY java file is windows 7 update 7. i know there should be another java file (under start>control panel>programs>uninstall a program) but i removed them all. i removed them all because i know that sometimes if minecraft isnt working you reinstall java, but i didnt know i wasnt supposed to uninstall that. also, now that ive reinstalled it, the 2nd file isnt there. But just for the record, my lag problems were there before i accidently removed the second java file. and no, i dont know what it was called.
operating system: windows 7
processor: intel core i7
java: windows 7 update 7
(dont know what else i need to put up)
THANX