Hi Anusha--I highly recommend you engage Support, as they will be better equipped to help you with this issue. When you do that, this information will be helpful to them:
During what operation (or on what screen) did you get the error about disk space being full?
What specific error is thrown when you attempt to start Tableau Server?
It would also be a good idea to proactively use the tabadmin ziplogs command to gather info they will need as well.
I hope you can get it resolved quickly!
+1 to what Matthew said but also ensure that there is still plenty of space on the drive. Did you check how much space "cleanup" created? You may have to move or delete other items then restart the machine.
Hopefully this has been resolved for you.....never a good feeling when servers refuse to come up and the affected users come at you with pitchforks
Very curious what the issue was though, I recall running out of disk space on a test server before and didn't have this problem.
Make sure you set up some proper monitoring on your server to alert you when the disk is getting full so you can take action before the system craps out.
Some info about monitoring here