Unlikely that that was the actual cause. You can have no space left on your primary drive and the operating system will still boot. this is because files/applications that are opened on boot are read into volatile memory, not hard drive space. there is an exception to that... if you dont have enough ram then there is usually a page file (swap space) reserved on the hard drive. but this is already reserved.
digishutterbug wrote: When this happened to me I had so many photos on my harddrive that there was not enough room for the strtup files to run. I don't really remember what I did, but I think I booted up in safe mode and moved enough photos onto an external drive to allow the startup files to run. If you have a lot of photos on you hard drive you might want to try that.