Unable to copy / backup PST

1. my pst size is 15 gb - i lost track of its size and forgot to maintain it under 2gb
2. I use outlook 2010

I could not copy the mails to another pst / server or copy the pst to another drive in the computer or . to the external hard drive. Data file check in outlook is running for the last 10 days and does not seem to end.

I have tried the following
1. Run scan pst - did not work. ended with the error after phase 1(in use by other applications error) - but it was not mapped in outlook and outlook was not running.
2. Copy it to external hard disk through various means - did not work (copied upto 12 gb and then failed with hard disk error message)
3. Compact tool in Mail - does not work
4. Zip and copy the file - does not work (same error as copy, went upto 9 gb and then failed)
5. I have tried to copy the mails folder by folder to exchange server (i have 25gb space in the server) - it worked for few folders, then it stopped saying pst is not available or sometimes that windows search aborted and hence needs to restart the outlook
6. i have disabled windows search and tried #5, did not work as well

Based on the error, it looks like a hard disk error - ran the chkdsk through command prompt, it was running forever and i had to abort it after the night with 0% progress made.

Help: I need to recover the mails in the pst - what is my best option?