From the sounds of it you have spyware/malware or similar on the system, and this is opening IE by itself (hence it reopens when you end the process) and it'll be doing who knows what, using a huge amount of processor time and memory. I've had this many times before, and it's always been malware and the like.
Many things you can do ... download and run adaware, spybot search and destroy, or any other spyware removal programs. Run an antivirus program and do a full system scan. You could do all these in one by googling windows one livecare or whatever it's called now, and do an online scan. Personally, after that I'd also install Adaware and Spybot. There's a little download called ComboFix which also gets rid of bad stuff from the system, can't remember what specifically, but I think it's hard to remove stuff that other detection software either misses or can't remove effectively. Just search for combofix, or adware combofix - you'll find it.
If any of the above helps, do come back on here and say so - it helps other people as well as lets people like me know if our info is useful or not.