out of space on my presario rp. need to clear space to defrag.

I recommend purging the hard drives of clutter with Windows Disk Cleanup, ATF Cleaner or CCleaner. If using CCleaner, uncheck the option to install the Yahoo toolbar during installation. Before first use, go to Options > Settings > Advanced and ensure Only delete files in Windows Temp folders older than 24 hours is unchecked. Know your site credentials (user names and passwords) for sites you frequent before cleaning; you may have to login again at next visit.

Windows Disk Cleanup Note: One distinct advantage Windows Disk Cleanup has over all other cleaners is that it also has the option to delete all but the most recent Restore Point. This can be significant as malicious code can hide there too. But I caution this option, found under the More Options tab, should be used only after careful consideration. If experiencing a problem that first appeared within the last couple days, do not use this option until sure System Restore can not be used to fix it. If the computer is running fine otherwise, and you are doing your weekly supplemental scans and want to root out as many potential malware hiding places as possible, I recommend setting a new Restore Point, and then use this Disk Cleanup option to clear out the old points.

Go through your Add and Remove Programs list in Control Panel and uninstall any program you installed but don't use.

Hopefully that will free up enough to allow defrag to run. Be sure to run defrag from Safe Mode too as that will ensure the most efficient defrag.