The HDD being the 5400rpm type will be slow but you would be used to that so that is not the issue and there looks to be nothing amiss with the drive itself.
Only two other suggestions i`m afraid, upgrading the RAM so that it works in dual channel and clean installing Windows and the system drivers.
Edit to add: The below from your Speccy report;
Total memory slots: 2
Used memory slots: 1
Free memory slots: 1
Size: 8192 MBytes
Channels #: Single
DRAM Frequency: 797.9 MHz The RAM being in single channel means that it is only working at 50% of what it can, 800MHz as opposed to 1600MHz.
CAS# Latency (CL): 11 clocks
RAS# to CAS# Delay (tRCD): 11 clocks
RAS# Precharge (tRP): 11 clocks
Cycle Time (tRAS): 28 clocks
Command Rate (CR): 1T
Memory Usage: 49 % Because the RAM is only working in single channel a lot more is being used, almost half of your RAM is being used when the computer is not under any load.
Total Physical: 7.84 GB
Available Physical: 3.96 GB
Total Virtual: 12 GB
Available Virtual: 7.85 GB