I cleaned up my disk[C:] using Disk Cleanup.I ticked all the items in Files to Delete section and clicked "OK".After that,when I opened Mozilla or IE9 it will stay on loading and will not connect.But If i open Chrome it will connect and I can surf.what is the problem?
I highly doubt that the disk clean-up created these problems, even if you check everything. It's not supposed to delete any system files or prevent applications to work. I would be afraid it might be a virus or something. In any case, if it's really the disk clean-up that caused this you can always try system restore and go back before the clean-up.