Loss of harddrive space and a huge error log

I'm not sure that I am posting in the right place, but here goes. I have a Laptop with Vista Home Basic. Recently I noticed that I have been losing hard drive space. Even after removing unnecessary programs I still keep losing space. I am down 4.48 GB out of 218 GB. I've run multiple virus scans, malware, and spyware scans and found nothing. Finally I asked for some advice on another forum and someone suggested that I download Windirstat. I did that and found that one file is taking up all the space. It is an error log found in Commonfiles/Dell/apache/logs. I can't delete the file wih what I've done so far. I started with a regular delete command and then tried to take ownership of the file. I've retried moving it and renaming it. Any advice would helpful. I don't want to have to set it back to factory but if that's the only thing I can do- I will.

Welcome
If you are sure that you do not need the file, have you gone directly to the log? Go to the C drive and then click on the various folders until you get to the log.
First, you may want to contact Dell, to make sure the log is not necessary and how they suggest how it be done.

This may help: Win Vista - Error Log over 100GB - PC Perspective Forums

It would appear that it's yet another example of Dell bloatware causing mayhem. Their support may be of assistance if all else fails.