MS IIS 5 server is hacked leaving undeletable folders and files

I have a small server I use for my home business and use it mainly for anyone who needs to send a large file that will not go through email. I have an anonymous UPLOAD FTP account that I open up to receive these. From time to time I forget and leave this open (I know this is stupid but I thought I could just erase anything that was put there because the small drive would fill up real soon). However, I see someone has hacked into my server and put a bunch of trash that I cannot delete because when I try to delete it, Windows 2K says "cannot find the specified file". I have spent 2 days researching this and cannot find any reference of how to correct this. I did find some reference to looking at the security tab for these files but the security tab is missing! I found some tools which are supposed to set owners for files and they don't work on these files. Here is the log from where the hacker attacked below. Any help would be appreciated. I don't want to have to rebuild my server if possible:  

#Software: Microsoft Internet Information Services 5.0

#Version: 1.0

#Date: 2002-12-30 06:38:21

#Fields: time c-ip cs-method cs-uri-stem sc-status

06:38:21 80.11.214.63 [1]USER anonymous 331

06:38:21 80.11.214.63 [1]PASS anonymous@on.the.net 230

06:38:24 80.11.214.63 [1]sent
/upload/com3+/lpt2+/com3+/d/%15%20%d%D_FCT+/f/.GR+/h/aux+/j/%15%20%+by+Lorg% d%D+/divx/rpc-acb.043 550

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06:54:31 80.11.214.63 [1]created rpc-acb.043 226

06:54:32 80.11.214.63 [1]sent
/upload/com3+/lpt2+/com3+/d/%15%20%d%D_FCT+/f/.GR+/h/aux+/j/%15%20%+by+Lorg% d%D+/divx/rpc-acb.044 550

07:10:38 80.11.214.63 [1]created rpc-acb.044 226 Received on Tue Dec 31 14:35:16 2002