Thank you for using the Dell Community Forum.
At the link below is the online manual for your system. It gives instructions for removing and reinstalling the hard drive.
Inspiron 1545 User Manual <ADMIN NOTE: Broken link has been removed from this post by Dell>
The issue might be related to the Hard drive, the connectors or with the Motherboard. We will not be able to identify the exact issue without complete troubleshooting. Please let me know the exact nature of the issue that you are facing. This will help us provide a faster resolution.
I hope this helps.
Please let us know in case of any queries.
Thanks and regards