You do not really offer the version of Windows you are running, or details about your hardware.

You might try this Microsoft page and see if it helps.

https://answers.microsoft.com/en-us/windows/forum/windows_7-update/msvcr120clr0400dll/debbc134-f4b2-4dde-8667-78560e3b0b2b?auth=1

You may also want to run the following on your machine and verify a few things that will check if hardware and Windows are in order. This could take some time. Generally run in this order:

"chkdsk /f" from a command prompt, choose yes on next reboot.  Reboot

Create a Memtest86+ boot disk and complete at least one full test set scan of memory wit ZERO errors.

Reduce any overclocking of system memory, CPU, or GPU. Reset them back to system default speeds.

Run "Disk Cleanup" on C: and "Cleanup System Files" removing all updates cache and versions of previous Windows. Reboot.

Check for more updates. Apply all windows updates, including any .NET updates. Reboot

Make sure GPU driver is latest.

Uninstall any old applications or utilities no longer used.

Run CCleaner Registry cleaner and repair issues.  Reboot.

Run a Windows defender scan, and Malware Bytes scan, and repair issues found, reboot if issues found and re-run scans.

"dism /Online /Cleanup-Image /RestoreHealth" from an admin command line.  You should get:

[==========================100.0%==========================]

The restore operation completed successfully.

The operation completed successfully.

sfc /scannow from an admin command prompt.  Verify you get:

"Windows Resource Protection did not find any integrity violations."

repair any issues here.   Reboot and re-run if issues repaired until you get the message above.

Make sure Vegas is running the latest build for your version, reboot if upgrade is needed.

Verify Hardware temps are ok during playback and rendering with something like Speccy or another program like it.  Repair clogged heat fins or cooling issues if high temps are present.