NT-007,
Windows 10 can be somewhat of an issue depending on your hardware. You have a great processor and ample memory. I have found that Windows 10 can be slow on systems with 4GB RAM and slow HDDs.
- What model Lenovo laptop do you have?
- Please define how your system is slow. Just at boot up, browsing the Internet, constantly from boot up to shutdown? Did you check Task Manager to see what process(es) might be causing the slowness (using a lot of CPU or hard drive access)?
- Was the new HDD you purchased a SSD (solid state drive) or a regular hard drive? If a regular HDD, what speed is it (5400rpm or 7200rpm)? SSDs can dramatically increase speed on systems.
- For Internet access or you using a wireless or wired connection?
- What antivirus software are you running, standard Windows 10 Windows Defender or a third party product? Products such as Norton and McAfee can have a pronounced affect on some systems with low specs.
- Did you install Windows 10 Home or Pro on your system? Pro gives you more options to control updates. Home only allows you to delay updates for a certain number of days while Pro can be set up to inform you of updates but only download and install them at your convenience.
I have an over 10 year-old Lenovo Thinkpad (i7, 8GB RAM) that still works fine. I replaced the old mechanical hard drive with an SSD and it made a dramatic difference. Of course it still is not as fast as newer systems, but is very usable. It has been able to keep up with all the Windows 10 upgrades. There was an issue with last years v2004 for which I had to wait several months to install that version until a fix was available for the display adapter driver. That is one problem with the new upgrades that come twice a year. They tend to cause issues with older systems with drivers which are no longer compatible.
Good luck,
JohnD