Windows 7: Black screen of death with mouse cursor

Hi, im having a really tough problem here especially when im not really good with computers and such. But here's my problem, i just installed a Mac OS skin for Windows 7 for my notebook (well, i wanted to have a cool theme for it) and upon restart at the login screen where its supposed to show the welcome screen in my Windows, there is only this black screen and my mouse cursor available.

Ctrl+Alt+Delete did not work to my disappointment and all I know after hours browsing the net in my brother's old PC to search for a solution is to either do a startup repair or do a system restore. My hard drive is almost full so I can't do a backup in it as stated by the system when i tried a system restore and I do not have a boot-able Windows DVD for a startup repair.

Anyone can help me solve my dilemma please help me because the notebook contains all my work and I got to do a presentation in my university soon. Is there a way to solve this black screen of death problem without me having to lose my data?




By the way, my OS is Windows 7 Home Premium SP1 running on an Acer 4745G with 512MB of ATI Mobility Radeon HD 5470 and a 4GB of RAM.