My hard disk is loosing space... i dunno what to do help

Hi, yesterday as i was usng my PC i noticed that i have suddenly lost 10 GB of my hard disk space. after a bit of investigation i found a file called treestate.dat was created in my real player folder with that size. i deleted the file and gained the space back. However this morning i noticed that i have lost some more space again. i tries searcing for viruses but nothing was detected. i am currently still loosing space and i do not know what to do. please help can anyone help please

Take a read through this and then start a fresh thread in this forum and post a HJT log, and a brief description of your problem, and somebody will be along as soon as.
Helpers look for posts with zero replies which is why you need to start afresh and why i'll lock this one.