Thank you SOOOOO much, Mike!!! It is working now!!
This was the problem, same one that lots of others were having: The 5550's driver software (version 7.1) is apparently not compatible with XP SP2's "Data Execution Prevention" feature.
Go to My Computer, right click & select Properties. Choose the Advanced panel. Click the first Settings button, in the Performance Section. Choose the Data Execution Prevention panel. Choose the first radio button, "Turn on DEP for essential Windows programs and services only", not the second one "Turn on DEP for all ...."
I seriously HATE the DEP program. It has been wreaking havoc on my computer. This has been the worse computer week for me ever. Last week my computer stopped working and had to be fixed so I had no computer for 4 days. It was tested for hardware and system problems but passed. Likely Windows XP was corrupted, computer was wiped, and all programs had to be reinstalled.
Ever since I got my computer back this week I haven't been able to upload photos on my auction template service using my previous method. Yesterday I wasn't able to upload at all. I downloaded Java for the multiple upload and after that DEP kept forcing me to close Internet Explorer every time I tried to upload photos. So I deleted Java, emptied it from the recycle bin, and still couldn't upload photos. Finally I DID change the DEP settings yesterday to try to solve that forcing Internet Explorer to close problem. My friend finally figured out I had to uncheck the 'enable memory' option somwhere. Then had to download Java again and was able to upload photos several hours later.
Would have never guessed the DEP was responsible for the printer not printing too and since I didn't change any printer settings, didn't think to look there. I didn't have DEP before but it must have been necessary when XP was reinstalled? I wish I could just turn it off or delete it altogether but you can only turn it off with Windows Vista, not XP.