This is from the previous link concerning the HD 5450 specs. This is the minimum requirements to run the HD 5450: ATI Radeon™ HD 5450 Graphics
System requirements and recommendations:
The only thing I can say is some hardware in your computer is not compatible with the HD 5450. I don't know if it is the PSU or the Motherboard. Your cousin's computer is a newer model than the one you have. I can see that your motherboard does have PCIe slot.
The beeps (two short beeps) indicate, if your BIOS is by IBM, either PSU or Motherboard problem. Obviously, the HD 5450 is not compatible with your computer.
Open a AMD SUPPORT TICKET via Email Support: Email Form . Include a link to this thread and see what they say. Maybe they can tell you if the HD 5450 is compatible with your Lenovo Motherboard or PSU.
If the HD 5450 works in your cousin's computer it means something in your computer is not compatible with the HD 5450 GPU card. I would keep using the GT 8600 until you get an answer from AMD Support.
This User is having something similar to you :
He replaced the motherboard and now his GPU is working and recognized. This was his last comment that fixed his problem with his computer not recognizing his GPU card: GPU not detected, fans are spinning
Alright, I visited my local vendor and I had pretty interesting results.
My GPU seemed to work fine on other motherboards, even with PSUs at 300 Watt.
Meanwhile, the mainboard worked fine with GPUs (Obviously installed in the same spot). Apparently, my specific GPU just didnt work with that specific mainboard.
I just got a new mainboard and the problem's fixed.
Thank you very much, then I know it's the motherboard. I'm 100%, since my cousin has the same psu as me practically, what changes is the motherboard, since they are and I know it because they have a different pci-express port, and I say this because of the port color pci-express and other things .. I'll try to get a motherboard like my cousin's, anything I tell you. Thank you very much, could you give me your Facebook or something to be in contact with?
I am fairly active here at AMD Forums.
In my honest opinion, I believe a new updated motherboard will solve your problem. If it does, post back here again to let other Users know also.
I guess the cheapest way for you is to get another Motherboard that uses the same RAM Memory and CPU/APU. Be sure the new Motherboard is compatible with the RAM Modules and CPU/APU you now have installed and has a higher rated PCIe x16 slot.
I know that if you upgrade the motherboard, you have to replace the RAM and CPU/APU also which can get very expensive unless you upgrade the motherboard that uses the same RAM and CPU.
Note: I changed the link to the correct link in my previous comment concerning the User with similar problem. You may want to take a look at it now: GPU not detected, fans are spinning