Hi. In my laptop, the c drive was partitioned into c & d. C is only 10gb and d is 65 gb. So I deleted all files on partition d. Now it says unallocated partition with no drive letter. I tried to format it thinking ... by this it will be empty and I'll be able to merge it back to c drive. Cant do it. Please help

Use admin tools. Select start, run, type in compmgmt.msc /s. Then use disk managment. That would allow you to give it a drive letter or attach that space to a folder under C: If you want to merge then you need third party software to manage partition. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10

Even when using third party software you still must partition the unallocated space before you can merge it. Any merge could go bad so backup your personal files before attempting it.

Or alternatively most third part partition software will allow you to extend a partition into unallocated space. Quikest and easiest way to do it. Stuart