I work in a big corporation, and the disk space my team gets in the corporate file server is so low, I am considering turning my work PC into a file server.

I ask this community for links to tutorials, software suggestions, and advice in general about how to set it up.

My machine is an Intel Core2Duo E7500 @ 3GHz, 3 GB of RAM, Running Windows XP Service Pack 3. Upgrading, formatting or installing another OS is out of the question. But I do have Administrator priviledges on the PC, and I can install programs (at least for now).

A lot of security software I don't even know about is and must remain installed. But I only need communication whithin the corporate network, which is not restricted.

People have usernames (logins) on the corporate network, and I need to use them to restrict access. Simply put, I have a list of logins of team members, and only people in the list should access the files.

I have about 150 GB of free disk space. I'm thinking of allocating 100 GB to the team's shared files.

I plan monthly backups on machines of co-workers, same configuration. But automation of backups is a nice, unnecessary feature: it's totally acceptable for me to manually copy the contents to a different machine once a month.

Uptime is important, as everyone would use these files in their daily work.

I have experience as a python and C programmer, but no experience whatsoever as a sysadmin, and almost nothing of my programming experience is network programming. I'm a complete beginner in this.

Thanks in advance for any help.

EDIT

I honestly appreciate all the warnings, I really do, but what I plan to make available is mostly stuff that now is solely on DVDs just for space reasons.

It's 'daily work' to read them, but 'daily work write' files will remain on the corporate server.

As for the importance of uptime, I think I overstated it: a few outages are OK, it's already an improvement over getting the DVDs.

As for policy, my manager is kind of on my side, I will confirm that before making my move.

As for getting more space through the proper channels, well, that was Plan A, and it's still on the table... But I don't have much hope. I'm not as "core businees" as I'd like.