System Reboots Upon Connecting Digital Camera And Unable To Access W2k Directory

I recently (two weeks ago) upgraded my system from W98 to W2k. The first time I installed, the program , I did it keeping my w98 folders etc. Ther were some errors and I tried to re-install, choosing the overwrite option. (also downloaded service pack one! I tried to download service pack 4 but it told me there was not enough memory) I have been left with two W2k directories. I have been using the most recent one (the preferred one) and have slowly been copying my important files using my flash disk from the other W2k directory. The only problem I have had is that althought the drivers and soft ware are installed, everytime I connect and switch my digital camera on, the sytem reboots. Iwanted to "defrag " the preferred W2k directory but was told there was not enough disk space. I thought then to uninstall programs on the other W2k diectory that I was not using. ie. mainly software etc for which I have disk and have reinstalled on the preferred W2k directory. Well after I had finished I rebooted, and then the trouble began! I cannot get into the "preferred" W2k directory. I swear I did not change or remove any settings or programs.