Slow Start Up & Response Time, Possible HD Failure?

Hello,

About 2 weeks ago after watching movies on Amazon Prime my computer's performance started to deteriorate. I'm not sure if it's a coincidence or if they downloaded something onto my computer that's caused me problems, but that's when it started.

When I don't have to do a startup repair, my startup time now averages over 6 minutes. When I'm lucky enough to get my desktop to come up the performance drags (e.g. I click on the start menu and 1 minute later the menu opens). Periodically my system will also crash, usually when I'm online or if I'm using a scanner to try and determine if the hard drive is failing.

I've tried fixing the issue myself but I cannot seem to repair it and I need help. Below is a list of things I already tried.

1) Is it a virus/malware? I don't think so. Outside of the McAfee protection I have running, I scanned my computer with Kaspersky TDSSKiller, Anti-Malware Bytes, Hitman Pro, and ESET. All of them came back negative.

2) I tried doing a clean boot (disabling all startup programs) and no improvement. I then disabled all non-Microsoft starup services along with disabling all startup programs and again no improvement.

3) I updated the BIOS and no improvement

4) I ran CHKDSK to test my hard drive and nothing negative came back. However, if I run a test in the Pre-Boot System Assessment, the Short DST test now says it cannot locate my hard drive. On one of the earlier times I ran the test it came back with "Error code 0145. Msg: Error Code 2000-0145. Hard drive 0 - self test did not complete."

5) I reinstalled Windows 7 from Dell Datasafe back to factory condition and no improvement.

Some of the messages I receive when the computer crashes are:

1) Bad_System_Config_Info. Stop: 0x00000074. Physical memory dump failed with status 0xC000009C

2) Status: 0xC00000e9. Info: An unexpected I/O error has occurred

3) Kernel_Data_Inpage_Error. Stop: 0x0000007A

4) Stop: 0x000000F4

5) Event Viewer shows critical errors with Boot Performance Monitoring and Shutdown Performance Monitoring

I'm running Windows 7 Professional.

Hard Drive Manufacture: Seagate
Model: ST9750420AS
Capacity: 750 GB

Thanks.