Open vista Optimizer-System Cleaning -vista System Slimming-System Disk Content Analysis-Select All after Analysis, and click Start Slimming.

Enter the system disk and click Properties-Disk Cleanup-All User Files-OK.

The above steps can save more than half the space (compared with your 43G). My system now occupies 12G (flagship sp2).

Sp2 backup cleaning ... I will wait until you upgrade to sp2.

Here are the things you need in the future:

Clean up junk files-Select All to start searching junk files-Select All after searching-Clean up files.

Registry Cleaning-Scan Registry-Select All-Clean Registry. Ok, that's enough for today.