# Compile PyCrypto on Windows With Visual C++

Install Visual Studio 2008 SP1 Express Edition.

Go to the command prompt.

First, I had to set the following variable:

```C:>set VS90COMNTOOLS=C:Program FilesMicrosoft Visual Studio 9.0Common7Tools
```

Note the trailing backslash – that needs to be there. The value must also NOT be in quotes.

```C:>cd "Program FilesMicrosoft Visual Studio 9.0vcbin"
C:Program FilesMicrosoft Visual Studio 9.0VCbin>vcvars32
Setting environment for using Microsoft Visual Studio 2008 x86 tools.
```

Then, from your PyCrypto directory, run:

```python setup.py install
```

And it should install with no problem.